U.S. patent application number 13/821387 was filed with the patent office on 2013-07-04 for method for operating a drivetrain.
This patent application is currently assigned to ZF FRIEDRICHSHAFEN AG. The applicant listed for this patent is Bernd Doebele, Norbert Wiencek. Invention is credited to Bernd Doebele, Norbert Wiencek.
Application Number | 20130172148 13/821387 |
Document ID | / |
Family ID | 44629501 |
Filed Date | 2013-07-04 |
United States Patent
Application |
20130172148 |
Kind Code |
A1 |
Wiencek; Norbert ; et
al. |
July 4, 2013 |
METHOD FOR OPERATING A DRIVETRAIN
Abstract
A method for operating a drive train having a variable speed
transmission connecting a drive unit with an output drive. The
transmission has gears that can be selected by the driver and has a
clutch that can be manually actuated. The torque intended by the
driver is determined based on accelerator pedal actuation and the
drive unit is operated on that basis. Whenever the driver
disengages the clutch and changes gears, the torque intended by the
driver is not used for operating the drive unit, rather the drive
unit is automatically operated by a rotational speed control. In a
first phase rotational speed control, a target value is
automatically determined, that is independent of the current
transmission input speed, and used for the rotational speed
control. During a second phase, a target value which is dependent
on the current transmission input speed is used for the rotational
speed control.
Inventors: |
Wiencek; Norbert; (Hagnau,
DE) ; Doebele; Bernd; (Salem, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Wiencek; Norbert
Doebele; Bernd |
Hagnau
Salem |
|
DE
DE |
|
|
Assignee: |
ZF FRIEDRICHSHAFEN AG
Friedrichshafen
DE
|
Family ID: |
44629501 |
Appl. No.: |
13/821387 |
Filed: |
August 3, 2011 |
PCT Filed: |
August 3, 2011 |
PCT NO: |
PCT/EP2011/063331 |
371 Date: |
March 7, 2013 |
Current U.S.
Class: |
477/77 |
Current CPC
Class: |
F16H 63/502 20130101;
F16H 2061/0411 20130101; B60W 10/02 20130101; F02D 2200/1002
20130101; F02D 2200/101 20130101; B60W 10/11 20130101; F16H 2306/54
20130101; B60W 10/04 20130101; Y10T 477/6403 20150115; F02D 41/023
20130101; F16H 61/0403 20130101; F02D 31/007 20130101; F16H 59/18
20130101 |
Class at
Publication: |
477/77 |
International
Class: |
B60W 10/11 20060101
B60W010/11; B60W 10/04 20060101 B60W010/04; B60W 10/02 20060101
B60W010/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 9, 2010 |
DE |
10 2010 040 455.1 |
Claims
1-14. (canceled)
15. A method of operating a drive train by a drive unit in which a
multi-step variable speed transmission connects the drive unit with
an output drive, the transmission comprising a plurality of gears
that are selectable by a driver and having a clutch that is
manually actuatable by the driver and connected between the drive
unit and the multi-step variable speed transmission, the method
comprising the steps of: determining a torque intended by the
driver as a function of an actuation of an accelerator pedal of the
drive train by the driver; operating the drive unit based on the
torque intended by the driver; when the clutch is disengaged by the
driver and a gear change is carried out by the driver, terminating
using the torque intended by the driver for operating the drive
unit and automatically operating the drive unit by a rotational
speed control; during a first phase of the rotational speed
control, automatically determining and utilizing a target value for
the rotational speed control with the target value being
independent of current transmission input speed; and during a
second phase of the rotational speed control, utilizing another
target value which is dependent on the current transmission input
speed.
16. The method according to claim 15, further comprising the step
of automatically utilizing, during the second phase of the
rotational speed control, a target value for the rotational speed
control, which is dependent on an output rotational speed of the
transmission and a gear ratio of a gear engaged before the gear
change.
17. The method according to claim 15, further comprising the step
of automatically utilizing, during the second phase of the
rotational speed control, a target value for the rotational speed
control which corresponds to a filtered transmission input
speed.
18. The method according to claim 17, further comprising the step
of automatically attenuating a filtering effect of the filtering of
the transmission input speed with increasing time.
19. The method according to claim 17, further comprising the step
of automatically utilizing at the latest, during a synchronization
phase of the transmission, a target value for the rotational speed
control which corresponds to the transmission input speed.
20. The method according to claim 15, further comprising the step
of determining a duration of the first phase of the rotational
speed control over a constant, applicable period of time.
21. The method according to claim 15, further comprising the step
of limiting either a duration of the first phase of the rotational
speed control or a total duration of the first phase and the second
phase of the rotational speed control by a maximum period of
time.
22. The method according to claim 15, further comprising the step
of automatically terminating the rotational speed control when the
clutch is engaged by the driver.
23. The method according to claim 22, further comprising the step
of operating the drive unit, subsequent to the rotational speed
control, dependent upon a torque target value which is decoupled
from the torque intended by the driver, and the torque intended by
the driver limits the torque target value.
24. The method according to claim 23, further comprising the step
of raising the torque target value, when the torque intended by the
driver is greater than the torque target value, starting from a
last valid engine torque in the rotational speed control to the
torque intended by the driver.
25. The method according to claim 22, further comprising the step
of maintaining the decoupling of the torque target value from the
torque intended by the driver when the clutch is partially
engaged.
26. The method according to claim 22, further comprising the step
of completing the decoupling of the torque target value from the
torque intended by the driver when the clutch is completely
engaged.
27. The method according to claim 15, further comprising the step
of automatically activating a gear brake in order to reduce the
transmission input speed, when the clutch is completely disengaged
and when a transmission is in neutral and when a difference between
the engine torque and the transmission input speed is greater than
a first, upper limit value; and automatically deactivating the gear
brake, when a difference between the engine torque and the
transmission input speed, either reaches or falls below a second,
lower limit value.
28. The method according to claim 15, further comprising the step
of operating the drive unit independent of a torque target value
such that the torque target value is slowly adjusted to the torque
intended by the driver, when the clutch is completely engaged, not
during a gear change, in a push/pull change in the drive train.
Description
[0001] This application is a National Stage completion of
PCT/EP2011/063331 filed Aug. 3, 2011, which claims priority from
German patent application serial no. 10 2010 040 455.1 filed Sep.
9, 2010.
FIELD OF THE INVENTION
[0002] The invention relates to a method for operating a drive.
BACKGROUND OF THE INVENTION
[0003] A method for operating a drive train by means of a drive
unit and having a manual transmission connecting the drive unit and
an output drive is known from document DE 10 2008 042 385 A1. A
manual transmission refers to a multi-step variable speed
transmission, the transmission comprising a plurality of gears that
can be selected by the driver. According to the method disclosed
therein, it is suggested that a gear brake that is or that can be
brought into an operative connection with a transmission input
shaft be used for assisted shifting, in order to automatically
reduce a speed difference occurring on a gear clutch of the target
gear as a result of shifting. With this method according to DE 10
2008 042 385 A1, assisted shifting can already be provided to some
extent for a drive train having a manual transmission.
[0004] Although methods are already known from the prior art, by
means of which assisted shifting can be guaranteed on a drive train
having a manual transmission, there is a need for novel methods of
operating a drive train, by means of which assisted shifting on a
drive train having a manual transmission can be further
improved.
SUMMARY OF THE INVENTION
[0005] On this basis, the present invention's objective is based on
creating a novel method for operating a drive train. This objective
is achieved by a method according to the invention in which,
whenever the clutch is disengaged by the driver and when
furthermore a gear change is carried out by the driver, the torque
intended by the driver is not used to operate the drive unit.
[0006] Rather, according to the invention, the drive unit is
automatically operated by a rotational speed control when the drive
train is operated in this situation, of the drive train, wherein a
target value for the rotational speed control is determined
automatically such that a target value independent of the current
transmission input speed is used in a first phase of the rotational
speed control, and a target value dependent on the current
transmission input speed is used in a second phase of the
rotational speed control of the drive unit.
[0007] According to the invention, it is therefore suggested that
whenever a clutch drive is disengaged as a result of driver
actuation, and when a gear change is carried out by the driver, the
drive unit be automatically operated by a rotational speed control,
wherein the rotational speed control is subdivided into two phases,
namely into a first phase, in which a target value for the
rotational speed control is determined independently of the current
transmission input speed, and in a second phase, in which the
target value for the rotational speed control is determined
dependent upon the current transmission input speed. This makes it
possible to adapt the rotational speed of the drive unit to a
transmission input speed in a particularly preferred manner, in
order to guarantee the lowest possible speed difference between the
rotational speed of the drive unit and the transmission input speed
the next time the clutch is engaged after carrying out a gear
change, and therefore to minimize wear on the clutch.
[0008] According to an advantageous embodiment of the invention, a
target value for the rotational speed control is automatically used
during the second phase of the rotational speed control, the target
value being dependent on an output rotational speed of the
transmission and a gear ratio of the gear engaged before the gear
change, wherein a target value for the rotational speed control is
automatically used during the second phase of the rotational speed
control, which corresponds to the filtered, current transmission
input speed.
[0009] At the latest, in a synchronizing phase of the transmission,
a target value for the rotational speed control is automatically
used, which corresponds to the filtered, current transmission input
speed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Preferred developments of the invention can be derived from
the description that follows. Embodiments of the invention are
explained in greater detail with reference to the drawings, without
being limited thereto. In the drawings:
[0011] FIG. 1 a schematic configuration of a drive train;
[0012] FIG. 2 a state graph to illustrate the invention;
[0013] FIG. 3 a first timing chart to illustrate the invention for
an upshift; and
[0014] FIG. 4 a second timing chart to illustrate the invention for
a downshift.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] The invention relates to a method for operating a drive
train, wherein FIG. 1 shows a highly schematic diagram of an
exemplary drive train, wherein the inventive method can be
used.
[0016] Thus the drive train in FIG. 1 is equipped with a drive unit
1, an output drive 2 and a multi-step variable speed transmission 3
connecting the drive unit 1 and the output drive 2, the
transmission comprising a plurality of gears that can be selected
by the driver. Such a multi-step variable speed transmission having
gears that can be manually engaged is also known as a manual
transmission.
[0017] In addition, the drive train in FIG. 1 incorporates a clutch
4 that can be manually actuated by the driver, which connects the
drive unit 1 and the multi-step variable speed transmission 3.
[0018] In addition, FIG. 1 shows a clutch pedal 5 for the manual
actuation of the clutch 4, an accelerator pedal 6, which is known
as a gas pedal, as well as a brake pedal 7. The clutch pedal 5,
accelerator pedal 6 and brake pedal 7 can be actuated by the
driver.
[0019] In addition, the drive train of FIG. 1 incorporates a gear
brake 8, which is associated with the multi-step variable speed
transmission 3. The gear brake 8 is or can be coupled with a
transmission input shaft 9, wherein the clutch 4 also engages with
the transmission input shaft 9, via which the transmission input
shaft 9 can be coupled with a drive unit shaft 10. A transmission
output shaft 11 is in an operative connection with the output drive
2.
[0020] In accordance with the dashed arrows in FIG. 1, the above
mentioned components of the drive train exchange control-side data
with a control device 12 for operating the drive train. Thus a
rotational speed n1 of the drive unit 1, a rotational speed n9 of a
transmission input shaft, a rotational speed n11 of a transmission
output shaft, a driving speed v2 of the drive train, a clutch pedal
position a5, an accelerator pedal position a6, a brake pedal
position a7 and a clutch position signal x4 from a provided clutch
sensor (not shown) are provided as input data to the control device
12.
[0021] The control device 12 can deduce from the clutch position
signal x4 and/or the clutch pedal position a5, whether the clutch 4
is completely engaged, completely disengaged, or partially engaged
or partially disengaged. Preferably a distinction is made between
three operating positions or three operating ranges regarding the
position or status of the clutch 4, namely between a completely
disengaged clutch 4, a completely engaged clutch 4 and a partially
engaged clutch 4.
[0022] The control device 12 can derive a torque intended by the
driver from the accelerator pedal position a6 and/or brake pedal
position a7. Alternatively, a torque intended by the driver may
also be provided to the control device 12 from another control
device. A torque intended by the driver refers to a torque, on the
basis of which the drive unit 1 can be operated in such a way, that
the drive unit can provide an actual driving torque that
corresponds to the torque intended by the driver, wherein to that
end, a fuel quantity supplied to the drive unit 1 is typically
determined based on the torque intended by the driver.
[0023] A signal x3 of the transmission 3 is provided to the
transmission controller 12 as an additional input variable, wherein
the signal x3 of the transmission 3 concerns an output variable of
a so-called neutral switch 13 of the transmission 3. The signal x3
therefore provides information regarding whether the multi-step
variable speed transmission 3 of the manual transmission is in a
neutral position or not.
[0024] The drive train is operated dependent upon the above
mentioned input variables, namely dependent upon an evaluation of
one or more of the input variables as described and defined in
detail below, wherein the control device 12 according to FIG. 1
provides two output variables, Y1 and Y8, namely an output variable
Y1 for operating the drive unit 1 and an output variable Y8 for
operating the gear brake 8.
[0025] In the following it can be assumed that when operating the
drive train shown in FIG. 1, a distinction is made between the five
operating states 14, 15, 16, 17 and 18 shown in the state graph in
FIG. 2, wherein no shifting occurs in the multi-step variable speed
transmission 3 in the first operating state 14, and accordingly no
shift is carried out, and the clutch 4 is also completely engaged
in the first operating state 14.
[0026] Likewise, no shifting occurs and the clutch 4 is engaged in
the multi-step variable speed transmission 3 in the fifth operating
state 18. The operating states 14 and 18 differ, however, in terms
of an engine control intervention provided by the control device
12, the engine control intervention provided by the engine control
device 12 is not active in the first operating state 14, whereas in
the fifth operating state 18, the engine control intervention
provided by the engine control device 12 is active.
[0027] For the engine control intervention of the control device
12, it should be understood that in the case of non-active engine
control intervention, the drive unit 1 is operated on the basis of
the above mentioned torque intended by the driver. In the case of
an active engine control intervention, on the other hand, the drive
unit 1 is not operated on the basis of the above mentioned torque
intended by the driver, but rather, is operated as described in
detail below.
[0028] A shifting is carried out in the multi-step variable speed
transmission 3 in each of the operating states 15, 16 and 17,
accordingly a shifting in the multi-step variable speed
transmission 3 is active in these three operating states 15, 16 and
17, wherein the clutch 4 is disengaged or partially
disengaged/engaged and the engine control intervention provided by
the control device 12 is not active in the second operating state
15, wherein the clutch 4 is completely disengaged and the engine
control intervention provided by the control device 12 is active in
the third operating state 16, and wherein the clutch 4 is
disengaged or partially disengaged/engaged and the engine control
intervention provided by the control device 12 is active in the
fourth operating state 17.
[0029] When carrying out a shifting in the multi-step variable
speed transmission 3, the operating states 14, 15, 16, 17 and 14
are typically run though in succession.
[0030] In addition, it is possible that the operating states 14,
15, 17 and 14 will be run through in succession, namely when the
clutch 4 is only tapped and released by the driver.
[0031] It is also possible that the operating states 14, 18 and 14
will be run through, namely in particular in the case of a
push/pull change in the drive train outside of gear changes and
shifts.
[0032] Moreover the operating states 14, 15, 14 or 14, 15, 16, 14
can also be run through, namely when signals are absent in the
operating states 15 and/or 16.
[0033] The transition between the operating states 14 to 18 is
defined in accordance with FIG. 2 via so-called transition
conditions 19, 20, 21, 22, 23 and 24. Thus a transition from the
first operating state 14 into the second operating state 15 is
possible when the transition condition 19 has been met. A
transition can be made from the second operating state 15 into the
third operating state 16 when the transition condition 20 is met.
Then when the transition condition 21 has been met, a transition
can be made either from the second operating state 15 into the
fourth operating state 17 or from the third operating state 16 into
the fourth operating state 17. Then when the transition condition
22 has been met, a transition can be made from the fourth operating
state 17 into the first operating state 14 or from the fifth
operating state 18 into the first operating state 14. The
transition condition 23 defines the transition from the first
operating state 14 into the fifth operating state 18, whereas the
transition condition 24 defines the transition from the third
operating state 16 into the first operating state 14.
[0034] The individual operating states 14 to 18 and the transition
conditions 19 to 24 will be discussed in detail below.
[0035] As has been stated previously, no shifting occurs in the
first operating state 14 in the multi-step variable speed
transmission 3, and furthermore the clutch 4 is completely engaged.
A first operating state 14 refers to a rest state between two
shiftings. In the first operating state 14, the above mentioned
engine control intervention of the control device 12 is not active,
but rather in the first operating state 14, the drive unit 1 is
operated dependent upon a torque intended by the driver, which is
either determined by the control device 12 or provided by another
control device. As has been stated previously, the torque intended
by the driver depends on the accelerator pedal position a6. In the
first operating state 14, the output variable Y1, on the basis of
which the drive unit 1 is operated, corresponds to the torque
intended by the driver. In the first operating state 14, the gear
brake 8 is disengaged via the output variable Y8. In addition, in
the first operating state 14, the current gear ratio is calculated
from a ratio of the transmission input speed n9 and the output
rotational speed of the transmission n11, wherein an actual gear
currently engaged in the multi-step variable speed transmission 3
can be determined or calculated dependent upon this gear ratio. The
gear ratio and the actual gear can be stored in the control device
12.
[0036] In the second operating state 15, in which a shifting occurs
in the multi-step variable speed transmission 3, the clutch 4 is
disengaged such that the clutch 4 is therefore partially disengaged
or partially engaged in the second operating state 15. In the
second operating state 15 there is no intervention of the control
device 12 in the engine torque, but rather the drive unit 1 is also
operated dependent upon the torque intended by the driver in the
second operating state 15. The driver therefore also influences a
reduction of the torque of the drive unit 1 in the second operating
state 15 by actuating his accelerator pedal a6 himself. The output
signal Y1 issued by the control device 12 therefore also
corresponds to the torque intended by the driver in the second
operating state 15. Furthermore the gear brake 8 is deactivated via
the output variable Y8 in the second operating state 15.
[0037] The clutch 4 is completely disengaged in the third operating
state 16, in which a shifting is likewise active in the multi-step
variable speed transmission 3. According to the invention, it is
suggested that the torque intended by the driver not be used to
operate the drive unit 1 when the clutch 4 is completely disengaged
by the driver and further, when the driver carries out a gear
shifting in the multi-step variable speed transmission 3, thus when
the third operating state 16 is present, but rather, the drive unit
1 is operated independently of an intervention by the control
device 12, namely in such a way that the drive unit is
automatically operated by a rotational speed control in the third
operating state 16.
[0038] This rotational speed control, which is specified by the
control device 12, occurs automatically, in such a way that in a
first phase of the rotational speed control, a target value that is
independent of the current transmission input speed n9 is used for
the rotational speed control, wherein, in a phase of the rotational
speed control that is subsequent to the first phase, a target value
that is dependent on the current transmission input speed is used
for the rotational speed control of the drive unit 1.
[0039] The target value that is used during the second phase of the
rotational speed control in the third operating state 16 is
preferably dependent on an output rotational speed of the
transmission n11, as well as being dependent on a ratio of the
transmission 3 of the gear engaged in the transmission 3 before the
gear change. The relevant transmission output speed n11 before
carrying out a gear change is multiplied by the relevant gear ratio
of the last gear engaged before the gear change, in order to
provide the target value for the first phase of the rotational
speed control in the third operating state 16 in this way. The
ratio needed for this was calculated in the first operating state
14.
[0040] According to an advantageous embodiment of the invention,
the target rotational speed for the rotational speed control of the
vehicle speed v2 is tracked during the first phase of the
rotational speed control in the third operating state 16.
[0041] In addition, the current transmission input rotational speed
9 is preferably filtered during the second phase of the rotational
speed control, and a theoretical target value for the rotational
speed control is calculated from the filtered, current transmission
input speed n9 of the transmission 3, although, however, this is
not used for rotational speed control during the first phase.
Rather, the rotational speed control is done during the first phase
on the basis of the target value, which is dependent on the
relevant transmission output speed before the gear change as well
as on the gear that is engaged before the gear change.
[0042] At the end of the first phase of the rotational speed
control, which is preferably defined by a constant, applicable
period of time, the filtered, current transmission input speed n9
is used as a target rotational speed for the rotational speed
control during the subsequent second phase of the rotational speed
control, wherein the filter effect for the filtering of the
transmission input speed n9 is attenuated when forming the target
value for the speed rotational speed control with increasing time.
The current, unfiltered transmission input speed is used as a
target rotational speed for the rotational speed control at the
latest during and after a synchronization phase of the transmission
3.
[0043] The foregoing rotational speed control, namely the duration
of the second phase of the rotational speed control or the total
duration of the first phase and the second phase of the rotational
speed control, is limited by an applicable, maximum time period, at
the end of which the rotational speed control is automatically
terminated. After this maximum time period has been exceeded, the
foregoing rotational speed control is no longer allowed until the
next shifting.
[0044] The foregoing rotational speed control is also terminated
immediately when the clutch 4 is no longer fully disengaged. Thus,
if the clutch 4 is engaged by the driver, the foregoing rotational
speed control is automatically terminated, which means both from
the first phase of the rotational speed control and from the second
phase of the rotational speed control.
[0045] The filtering of the current transmission input speed n9 in
order to determine the target values for the rotational speed
control during the second phase of the same can be obtained using a
sliding mean-value formation. The filtering effect of this
filtering decreases as the time of the rotational speed control
increases.
[0046] For the rotational speed control, the corresponding target
value for the rotational speed control is compared with a measured
actual value of the rotational speed n1 of the drive unit 1,
wherein, dependent upon a control deviation, a controller generates
a manipulated variable so that the actual rotational speed is
brought closer to or follows the target rotational speed. This can
be obtained using a PID controller. Alternatively, this can also be
obtained based on the characteristic map. The manipulated variable
of the controller, which outputs the same in order to bring the
actual rotational speed closer to the target rotational speed,
typically relates to the target rotational speed for the drive unit
1. The target rotational speed hereby determined by the controller
can be corrected with an offset value to compensate for frictional
losses of the drive unit 1.
[0047] The breakdown of the foregoing rotational speed control in
the first phase and the second phase has the advantage that, at the
start of the first phase, in which the current transmission input
speed may still be subject to string oscillations, a target value
for the rotational speed control that is independent of the current
transmission input speed can be used. Only during the second phase
is a target value for the rotational speed control used that is
dependent on the current transmission input speed, wherein any
oscillations of the transmission input speed can be filtered if
necessary.
[0048] Then, when the rotational speed control in the third
operating state 16 is terminated and the third operating state 16
is still active, or when a transition is made to the fourth
operating state 17 by engaging the clutch, an intervention is made
via the control device 12, namely in such a way that the drive unit
1 is operated dependent upon a torque target value, which is
essentially decoupled from the torque intended by the driver,
which, however, is limited by the torque intended by the
driver.
[0049] Accordingly, the control device 12 does not specify a target
value for the rotational speed for operating the drive unit in the
fourth operating state 17 and in the third operating state 16, when
the rotational speed control has been terminated but rather,
specifies a torque target value, which is essentially decoupled
from the torque intended by the driver, however which is limited by
the torque intended by the driver. The last valid target value for
the engine speed in the third operating state 16 based on the
rotational speed control serves as a starting value for this torque
target value, wherein when the torque target value is less than the
torque intended by the driver, the torque target value is increased
to the torque intended by the driver starting from the last valid
target value for the engine speed in the rotational speed control.
The increase in the torque target value to the torque intended by
the driver dependent upon the actuation of the accelerator pedal
can be obtained continuously or in several steps.
[0050] Then, when the clutch 4 is partially engaged and the torque
target value corresponds to the torque intended by the driver, the
engine control intervention is not deactivated by the control
device 12. However, when the clutch 4 is completely engaged, and
the torque intended by the driver and the torque target value are
equivalent, the engine control intervention is deactivated by the
control device 12 and the drive unit 1 is subsequently operated
based on the torque intended by the driver.
[0051] As has been stated previously, the fifth operating state 18
is an operating state not occurring during a shifting, therefore in
which no shifting occurs in the transmission 3 and furthermore, in
which the clutch 4 is completely engaged.
[0052] The fifth operating state 18 preferably corresponds to a
push/pull change in the drive train, wherein in a push/pull change
in the drive train, the drive unit 1 is operated via an engine
control intervention by the control device 12 dependent on a torque
target value, such that the torque target value is adjusted with a
delay to the torque intended by the driver dependent on the
actuation of the accelerator pedal.
[0053] This engine control intervention for the push/pull change
preferably only occurs when the driver moves the accelerator pedal
6 from a thrust position, which is defined, for example, by an
accelerator pedal actuation a6 of less than 3%. With an accelerator
pedal setting a6 below this thrust position, the torque target
value is set approximately to zero, however it is not yet used in
the operation of the drive unit 1. Only when the accelerator pedal
has been moved from the thrust position, when the accelerator pedal
angle a6 is greater than or equal to 3%, for example, is a torque
target value specified, which is adjusted slowly to the torque
intended by the driver. Here, the torque intended by the driver
serves as a maximum value, with the result that when the torque
intended by the driver is smaller than the torque target value, the
torque intended by the driver is used for operating the drive unit
1, and that when the torque intended by the driver is greater than
the torque target value, the torque target value is slowly brought
closer to the torque intended by the driver. Then, when the torque
target value reaches the torque intended by the driver, the fifth
operating state 18 is abandoned, a change is made into the first
operating state 14 and this engine control intervention, which is
permitted only once per push/pull change, is terminated.
[0054] The transition condition 19 for switching from the first
operating state 14 to the second operating state 15 is met when the
coupling status of the clutch 4 changes from a completely engaged
to a partially engaged coupling, when the input signals of the
control device 12 are valid, when a vehicle speed v2 is greater
than a specified limiting value, and when an ignition of the
vehicle is activated.
[0055] The transition condition 20 for switching from the second
operating state 15 to the third operating state 16 is met when the
coupling status has changed from a partially engaged to a
completely disengaged state, moreover when the input signals of the
control device 12 are valid, furthermore when the vehicle speed is
greater than aforementioned limiting value, when the ignition is
activated.
[0056] The transition condition 21 for switching from the third
operating state 16 to the fourth operating state 17, or for
switching from the second operating state 15 to the fourth
operating state 17 is met when the clutch 4 is engaged and the
coupling status is then partially engaged, moreover when the input
signals of the control device 12 are valid, when the vehicle speed
is greater than the aforementioned limiting value, and when the
ignition of the vehicle is activated.
[0057] A change from the fourth operating state 17 into the first
operating state 14 as well as a change from the fifth operating
state 18 into the first operating state 14 in the sense of the
transition condition 22 occurs when the clutch 4 is completely
engaged and moreover when a torque target value for operating the
drive unit 1 is greater or equal to the torque intended by the
driver. Alternatively, the transition condition 22 is met when one
or more of the input signals of the control device 12 are below
par, or when the ignition of the vehicle is activated, or when the
vehicle speed is less than a limiting value.
[0058] The transition condition 23 for switching from the first
operating state 14 to the fifth operating state 18 is met when the
clutch 4 is engaged, moreover when the accelerator pedal is
transferred from the thrust position into a pull position, and
furthermore when input signals of the control device 12 are valid,
the vehicle speed is greater than a limiting value and the ignition
of the vehicle is activated.
[0059] A change from the second operating state 15 to the first
operating state 14 in the sense of the transition condition 24
occurs when either at least one input signal of the control device
12 is invalid, or when the vehicle speed falls below a limiting
value, or when the ignition of the vehicle is deactivated.
[0060] According to an advantageous embodiment of the method
according to the invention, when the clutch 4 is fully disengaged
and when carrying out a shifting, or in other words when the third
operating state 16 is present and moreover when the neutral switch
13 for the transmission 3 according to the signal x3 indicates that
the transmission 3 is in a neutral setting, the gear brake 8 can be
automatically deactivated via the output signal Y8 of the control
device 12, namely when a difference between an engine speed n1 of
the drive unit and a preferably filtered transmission input speed
n9 is greater than an applicable, first upper limiting value. Then,
when this difference between the engine speed n1 and the
transmission input speed n9 subsequently reaches or falls below a
second lower limiting value, the gear brake 8 is then automatically
deactivated, again via the output signal Y8. In addition, the gear
brake 8 is then deactivated when a transition condition from the
third operating state 16 is met in another operating state, or in
other words when the third operating state 16 is no longer
valid.
[0061] In addition, the gear brake 8 is automatically deactivated
when the clutch 4 is no longer completely disengaged and/or when
the neutral switch 13 signals to the transmission 3 that the
transmission 3 is no longer in neutral.
[0062] FIGS. 3 and 4 show a plurality of temporal signal courses
over the period of time t, which may be formed when using the
method according to the invention, namely in FIG. 3 for an upshift
and in FIG. 4 for a downshift, wherein in FIGS. 3 and 4 each show
an actuation of an accelerator pedal a6, a clutch pedal actuation
a5, an engine speed n1, a transmission input speed n9, a torque
intended by the driver MFW, dependent on the actuation of the
accelerator pedal, an actual rotational speed M1-IST of the drive
unit 1, a torque target value M1-SOLL for the drive unit 1, an
actuation signal Y8 for the gear brake 8, as well as a signal Z are
plotted over a period of time t. The signal Z provides information
regarding the status of the clutch 4, or, in other words,
information about whether the clutch 4 is completely engaged,
completely disengaged, or partially engaged or partially
disengaged.
[0063] In the case of the upshift in FIG. 3, the driver retracts
the actuation of the accelerator pedal a6 at time t0, wherein at
time t1, the clutch is actuated and the coupling status is changed
from completely engaged to partially engaged. At time t2, the
clutch 4 is completely disengaged, wherein the third operating
state 16 is then present, in which a rotational speed control
initially occurs. The first phase of the rotational speed control,
in which a target value for the rotational speed control that is
independent of the transmission input speed n9 is used, extends
between the times t2 and t4, and the first phase of the rotational
speed control is therefore labeled t. In FIG. 3 it can further be
seen that at time t3, the gear brake 8 is activated via the signal
Y8 until time t4, in order to decelerate the transmission input
speed n9.
[0064] At time t5 the synchronization in the transmission begins
and a shift is made to the new gear, wherein at time t6, the
synchronization is completed and the gear is engaged. At time t7,
the driver starts to accelerate again by actuating the accelerator
pedal 6, wherein at time t8, the second phase of the rotational
speed control ends. Subsequently at time t8, a rotational speed
control is therefore no longer performed for operating the drive
unit 1, but rather a torque target value M1-SOLL is specified,
which is basically decoupled from the torque intended by the driver
MFW, limited, however, to a maximum by the torque intended by the
driver MFW. The actual engine torque M1-IST follows the torque
target value M1-SOLL. At time t9, the clutch changes from partially
engaged to completely engaged. At time t10, the torque intended by
the driver MFW and the torque target value M1-SOLL are equal, so
that the engine control intervention is completed and the operation
of the drive unit 1 is carried out based on the torque intended by
the driver MFW. In FIG. 3, the limiting values for the speed
difference between the transmission input speed n9 and the engine
speed n1, at which the gear brake 8 is activated or deactivated
respectively, are represented by n1 or n2 respectively.
[0065] In the case of the downshift in FIG. 4, the driver begins to
retract the accelerator pedal position a6 likewise at time t0, and
therefore with an accelerator release, wherein at time t1, the
coupling status is changed from completely engaged to the status of
partially engaged. At time t2, the status is changed from partially
engaged to completely disengaged, wherein the first phase of the
rotational speed control occurs starting at time t2, until time t4.
At time t4, a changeover is made to the second phase of the
rotational speed control, wherein the synchronization process first
begins at time t3 and a gear is engaged in the transmission. At
time t5, the synchronization process in the transmission is
completed and a new gear is engaged in the transmission 3.
[0066] At time t6, the driver starts to accelerate again by
actuating the accelerator pedal 6, wherein at time t7, the second
phase of the rotational speed control ends and a torque target
value M1-SOLL for operating the drive unit is specified, which is
essentially decoupled from the torque intended by the driver MFW,
which, however, is limited by the same. At time t8, the coupling
status changes from partially engaged to completely engaged. At
time t9 the torque intended by the driver MFW and the target torque
M1-SOLL are equal, so that the engine control intervention is again
completed and the operation of the drive unit 1 is based on the
torque intended by the driver.
REFERENCE CHARACTERS
[0067] 1 drive unit
[0068] 2 output drive
[0069] 3 multi-step variable speed transmission/manual
transmission
[0070] 4 clutch
[0071] 5 clutch pedal
[0072] 6 accelerator pedal
[0073] 7 brake pedal
[0074] 8 gear brake
[0075] 9 transmission input shaft
[0076] 10 drive unit shaft
[0077] 11 transmission output shaft
[0078] 12 control device
[0079] 13 neutral switch
[0080] 14 operating state
[0081] 15 operating state
[0082] 16 operating state
[0083] 17 operating state
[0084] 18 operating state
[0085] 19 transition condition
[0086] 20 transition condition
[0087] 21 transition condition
[0088] 22 transition condition
[0089] 23 transition condition
[0090] 24 transition condition
* * * * *